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In any programming language, a reserved word or a reserved identifier is a word that cannot be used as an identifier, such as the name of a variable, function, or label. Thus, it is reserved and cannot be used for defining any of these. This is a syntactic definition, and a reserved word may have no meaning. In this article, we will discuss some of the JavaScript reserved words and their description.
JavaScript Reserved Words
Here is a list of JavaScript Reserved words along with their definition:
| Reserved Words | Description |
abstract | Abstract is a non-access modifier which is applicable for classes, methods but not variables. |
arguments | Argument is an array-like object lists the arguments and a few other properties. |
await | The keyword Await makes JavaScript wait until the promise returns a result. |
boolean | Boolean is used as a function to get the value of a variable, object, conditions, expressions, etc. in terms of true or false. |
break | It breaks the loop and continues executing the code after the loop. |
byte | This uses the javascript typeof() operator to detect what kind of type is variable x and y. |
case | The switch statement evaluates an expression. The value of the expression is then compared with the values of each case in the structure. |
catch | This statement allows you to define a block of code to be executed if an error occurs in the try block. |
char | The char keyword is a data type that is used to store a single character. |
class | Classes are another way of writing constructor functions which can be used in order to create a new object using the new keyword. |
const | The const keyword is used to declare the constant in the function scope. |
continue | Continue statement jumps over one iteration in the loop. |
debugger | This statement stops the execution of JavaScript and calls the debugging function. |
default | The default keyword can be within a switch statement, or with an export statement. |
delete | You can use the delete keyword to delete the value of the property and the property itself. |
do | The do/while statement is used when you want to run a loop at least one time. |
double | JavaScript numbers are always stored as double precision floating point numbers |
else | It is a part of JavaScript’s Conditional Statements and you can use this to perform different actions based on different conditions. |
enum | The enum keyword declares an enumerated type. |
eval | The eval() function evaluates or executes an argument. |
export | The export statement is used when creating JavaScript modules to export functions, objects, or primitive values from the module. |
extends | The extends keyword is used in class declarations or class expressions to create a class which is a child of another class. |
false | JavaScript includes a Boolean object to represent true or false. It considers null as false. |
final | Final keyword is used to state that a value, class, or method cannot be changed. |
finally | The finally statement lets you execute code, after try and catch, regardless of the result. |
float | JavaScript numbers are always stored as double-precision floating-point numbers. |
for | The for statement creates a loop that is executed as long as a condition is true. |
function | A function is a JavaScript procedure that performs a task or calculates a value. |
goto | The goto is accomplished in JavaScript using the break and continue keywords. |
if | You can use if to specify a block of code to be executed if a specified condition is true. |
implements | The implements keyword is used to implement an interface. |
import | The import keyword is used to call the function to import the module dynamically. |
in | The in operator returns true if the specified property is in the specified object or its prototype chain. |
instance of | The instanceof operator in JavaScript is used to check the type of an object at run time. |
int | It converts a primitive datatype, string, or array to its integer representation. |
interface | The interface keyword is used to declare a special type of class that only contains abstract methods. |
let | let allows you to declare variables that are limited to a scope of a block statement, or expression on which it is used. |
long | Long represents a 64 bit two’s-complement integer value |
native | The native keyword is applied to a method to indicates that the method is implemented in native code. |
new | The new keyword constructs and returns an object of a constructor function. |
null | Null in JavaScript that signifies ‘no value’ or nonexistence of any value. |
package | A package is a directory with one or more modules inside of it and a package.json file wich has metadata about the package. |
private | A private function can only be used inside of its parent function or module. |
protected | A public function can be used inside or outside of its parent function or module. |
public | The protected keyword is an access modifier used for attributes, methods and constructors, making them accessible in the same package and subclasses. |
return | Return statements cease execution in a function and return a value to the caller. |
short | It is used to represent an integer value in JavaScript. |
static | The static keyword defines a static method for a class. |
super | The super keyword is used to access and call functions on an object’s parent. |
switch | The switch statement evaluates an expression. |
synchronized | synchronous code is executed in a sequence where each statement waits for the previous statement to finish before executing. |
this | The JavaScript this keyword refers to the object it belongs to. |
throw | Throw is the keyword that is used to raise an exception. |
throws | The throws keyword indicates what exception type may be thrown by a method. |
transient | Transient is a variables modifier used in serialization. |
true | Boolean datatype returns either of two values i.e. true or false. |
try | The try statement allows you to define a block of code to be tested for errors while it is being executed. |
typeof | typeof is a JavaScript keyword that will return the type of a variable when you call it. |
var | var is used to declare the variable in JavaScript. |
void | The JavaScript void operator evaluates the given expression and then returns a value of undefined. |
volatile | Volatile keyword is a qualifier that is applied to a variable when it is declared. |
while | The while statement creates a loop that is executed while a specified condition is true. |
with | The with statement extends the scope chain for a statement. |
yield | The yield keyword returns an IteratorResult object with two properties and value. |
With this, we come to the end of this “javascript reserved words” article. I hope you found it informative.
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